Azolylalkyl phosphonic acid herbicides

ABSTRACT

Compounds having the general formula (I): ##STR1## and stereoisomers thereof, wherein R 1  and R 2  are each hydrogen, a cation, alkyl, cycloalkyl, aryl or aralkyl optionally substituted with halogen, nitro, alkyl, haloalkyl, alkoxy, haloalkoxy, phenyl, phenoxy, halophenyl or halophenoxy, or together form a ring; R 3  and R 4  are each hydrogen, alkyl, cycloalkyl, heterocyclyl, aryl or aralkyl optionally substituted with halogen, nitro, alkyl, haloalkyl, alkoxy, haloalkoxy, phenyl, phenoxy, halophenyl or halophenoxy; W is N or CH; X is oxygen or sulphur; ester and ether derivatives of the alcohol; and its acid addition salts and metal complexes. The compounds are useful as fungicides and for plant growth regulation.

This invention relates to triazole and imidazole compounds useful as fungicides, to a process for preparing them, to fungicidal compositions containing them, and to methods of using them to combat fungi, especially fungal infections in plants; and to regulate plant growth.

The invention provides a compound having the general formula (I):

Compounds of formula: ##STR2## and stereoisomers thereof, wherein R¹ and R² are each hydrogen, a cation, alkyl, cycloalkyl, aryl or aralkyl optionally substituted with halogen, nitro, alkyl, haloalkyl, alkoxy, haloalkoxy, phenyl, phenoxy, halophenyl, or halophenoxy, or together form a ring; R³ and R⁴ are each hydrogen, alkyl, cycloalkyl, heterocyclyl, aryl or aralkyl optionally substituted with halogen, nitro, alkyl, haloalkyl, alkoxy, haloalkoxy, phenyl, phenoxy, halophenyl, or halophenoxy; W is N or CH; X is oxygen or sulphur; ester and ether derivatives of the alcohol; and their acid addition salts and metal complexes.

The compounds have fungicidal activity and plant growth regulating activity.

The compounds of the invention contain at least one chiral centre. Such compounds are generally obtained in the form of isomeric mixtures. However, these and other mixtures can be separated into the individual isomers by methods known in the art.

Examples of suitable cations for R¹ and R² are alkali metal cations eg, Na⁺ or K⁺ or a quaternary ammonium cation eg, NH₄ ⁺, isoC₃ H₇ NH₃ ⁺ ; and sulphonium cations eg, Me₃ S⁺.

When R¹ and R² together form a ring with the adjacent oxygen atoms and the phosphorus atom they may comprise an alicyclic bridging group eg, --(CH₂)_(n) -- where n is 1-6, preferably 2-4.

The ester derivatives of the alcohol may be eg, acetyl, propionyl, benzoyl and substituted benzoyl; the ether derivatives may be methyl, ethyl, propyl, butyl, benzyl, and substituted benzyl.

The alkyl, haloalkyl, alkoxy or haloalkoxy groups may be straight or branched chain groups having 1 to 6, eg, 1 to 4, carbon atoms; examples are methyl, ethyl, propyl (n- or iso-propyl) and butyl (n-, sec-, iso- or t-butyl). Cycloalkyl groups may be cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

Examples of suitable substituents for the aryl and aralkyl groups, which are preferably phenyl and benzyl, are halogen (eg. fluorine, chlorine, or bromine), C₁₋₅ alkyl [eg. methyl, ethyl, propyl (n- or iso-propyl) and butyl (n, sec-, iso- or t-butyl)], C₁₋₄ alkoxy (eg. methoxy and ethoxy), halo-alkoxy (eg. trifluoromethoxy), haloalkyl (eg. trifluoromethyl), nitro, phenyl and phenoxy. The phenyl ring may be, for example, unsubstituted or substituted with 1, 2 or 3 ring substituents as defined above. The phenyl may have a single ring substituent in the 2-, 3- or 4-position. Examples of these groups are phenyl, 2- , 3- or 4-chlorophenyl, 2,4- or 2,6-dichlorophenyl, 2-, 3- or 4-fluorophenyl, 2,4- or 2,6-difluorophenyl, 2-, 3- or 4-bromophenyl, 2-chloro-4-fluorophenyl, 2-chloro-6-fluorophenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-ethoxyphenyl, 2-, 3- or 4-nitrophenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-t-butylphenyl, 2-, 3- or 4-trifluoromethylphenyl, 2-, 3- or 4-phenoxyphenyl, 2-, 3- or 4-phenylphenyl (2-, 3- or 4-biphenylyl), 2-chloro-4-methylphenyl, and 2-chloro-4-methoxyphenyl.

Heterocyclyl groups may be, for example, thienyl, pyridyl, furyl, or pyrimidyl.

The salts can be salts with inorganic or organic acids eg. hydrochloric, nitric, sulphuric, acetic, 4-toluene-sulphonic or oxalic acid.

Suitably the metal complex is one including, as the metal, copper, zinc, manganese or iron. It preferably has the general formula: ##STR3## wherein W, X, R¹, R², R³ and R⁴ are as defined above, M is a metal, A is an anion (eg. a chloride, bromide, iodide, nitrate, sulphate or phosphate anion), p is 2 or 4, y is 0 or an integer of 1 to 12, and m is an integer consistent with valency.

Examples of the compounds of the invention are shown in Table 1. These conform to formula I. ##STR4##

                                      TABLE I                                      __________________________________________________________________________     COMPOUND                                                                       NO      R.sup.1                                                                            R.sup.2                                                                            R.sup.3 R.sup.4 W  X mp (°C.)                                                                     COMMENTS                             __________________________________________________________________________     1       C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    2,4-di-Cl--C.sub.6 H.sub.3                                                             H       N  O 85-86                                     2       C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    4-Cl--C.sub.6 H.sub.4                                                                  H       N  O 88-89                                     3       C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    4-F--C.sub.6 H.sub.4                                                                   H       N  O 118-119                                   4       C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    4-Cl--C.sub.6 H.sub.4                                                                  H       CH O 123-125                                   5       n-C.sub.4 H.sub.9                                                                  n-C.sub.4 H.sub.9                                                                  4-F--C.sub.6 H.sub.4                                                                   H       N  O 83-84                                     6       i-C.sub.3 H.sub.7                                                                  i-C.sub.3 H.sub.7                                                                  4-F--C.sub.6 H.sub.4                                                                   H       N  O 131-132                                   7       H   H   4-F--C.sub.6 H.sub.4                                                                   H       N  O 185-186                                                                             HBr salt                             8       C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    4-CH.sub.3 O--C.sub.6 H.sub.4                                                          H       N  O                                           9       C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    H       4-Cl--C.sub.6 H.sub.4                                                                  N  O                                           10      C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    H       2,4-diCl-- C.sub.6 H.sub.3                                                             N  O                                           11      CH.sub.3                                                                           CH.sub.3                                                                           H       4-Cl--C.sub.6 H.sub.4                                                                  N  O                                           12      CH.sub.3                                                                           CH.sub.3                                                                           H       2,4-diCl-- C.sub.6 H.sub.3                                                             N  O                                           13      C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                    CH.sub.3                                                                               4-ClC.sub.6 H.sub.4.CH.sub.2                                                           N  O 156-158                                                                             Single                                                                         Isomer                               14       -t-C.sub.4 H.sub.9                                                                t-C.sub.4 H.sub.9                                                                  H       4-ClC.sub.6 H.sub.4.CH.sub.2                                                           N  O                                           __________________________________________________________________________

Compounds of general formula (I): ##STR5## can be prepared by treatment of a ketone of general formula (II): ##STR6## wherein R³, R⁴, and W are as defined above, with a compound of general formula (III): ##STR7## wherein R¹, R², and X are defined above, in the presence of caesium fluoride or potassium fluoride, or on basic or neutral alumina, usually in the absence of a solvent at room temperature according to the methods of F. Texier-Boullet, A. Foucaud (Synthesis, 1982, 165-166 and 916).

The compounds of general formula (II) can be prepared by methods set out in the literature (eg, ICI British Pat. No. 1,533,706 and ICI British Pat. No. 1,535,777).

In an alternative process the compounds of general formula (I) may also be prepared by treating an epoxide of general formula (IV) or a halohydrin of general formula (V): ##STR8## wherein R¹, R², R³, R⁴, X are as defined above, and Y is chlorine or bromine with 1,2,4-triazole or imidazole, each in the presence of an acid-binding agent or in the form of one of its alkali metal salts in a convenient solvent such as a dimethylformamide or acetonitrile.

The epoxides of general formula (IV) can be prepared by methods set out in the literature (eg, A. Meisters, J. M. Swan, Aust.J.Chem., 1965, 18, 168-172). The halohydrins of general formula (V) can also be prepared by methods set out in the literature (eg, F. Texier-Boullet, A. Foucaud, Synthesis, 1982, 165-166 and 916).

The salts and metal complexes of the compounds of general formula (I) can be prepared from the latter by known methods. For example, the complexes can be made by reacting the uncomplexed compound with a metal salt in a suitable solvent. The esters and ethers can be prepared from the parent compounds by usual procedures.

The compounds, salts and metal complexes are active fungicides, particularly against the diseases:

Piricularia oryzae on rice

Puccinia recondita, Puccinia striiformis and other rusts on wheat, Puccinia hordei, Puccinia striiformis and other rusts on barley, and rusts on other hosts e.g. coffee, apples, apples, vegetables and ornamental plants

Erysiphe graminis (powdery mildew) on barley and wheat and other powdery mildews on various hosts such as

Sphaerotheca fuliginea on cucurbits (e.g. cucumber),

Podosphaera leucotricha on apples and Uncinula necator on vines

Helminthosporium spp., Rhynchosporium spp. and

Pseudocercosporella herpotrichoides on cereals

Cercospora arachidicola on peanuts and other Cercospora species on for example sugar beet, bananas and soya beans

Plasmopara viticola on vines

Venturia inaequalis (scab) on apples

Further some of the compounds are active as seed dressing against: Fusarium spp., Septoria spp., Tilletia spp. (i.e. bunt, a seed borne disease of wheat), Ustilago spp., Helminthosporium spp. and Pseudocercosporella herpotrichoides on cereals.

The compounds can move acropetally in the plant tissue. Moreover, the compounds can be volatile enough to be active in the vapour phase against fungi on the plant.

They may also be useful as industrial (as opposed to agricultural) fungicides, e.g. in the prevention of fungal attack on wood, hides, leather and especially paint films.

The compounds are also useful for the treatment of candidiasis and human dermatophyte infections.

The compounds, and their derivatives as defined above, also have plant growth regulating activities.

The plant growth regulating effects of the compounds are manifested as for example a stunting or dwarfing effect on the vegetative growth of woody and herbaceous mono- and di-cotyledonous plants. Such stunting or dwarfing may be useful, for example, in peanuts, cereals such as wheat barley and rice, oil seed rape, field beans, sunflowers, potatoes and soya bean where reduction in stem height, with or without further advantageous effects such as stem strengthening, thickening and shortening, internode shortening, increased buttress root formation and more erect stem and leaf orientation, may reduce the risk of lodging and may also permit increased amounts of fertiliser to be applied. The stunting of woody species is useful in controlling the growth of undergrowth under power lines etc. Compounds which induce stunting or dwarfing may also be useful in modifying the stem growth of sugar cane thereby increasing the concentration of sugar in the cane at harvest; in sugar cane, the flowering and ripening may be controllable by applying the compounds. Stunting of peanuts can assist in harvesting. Growth retardation of grasses can help maintenance of grasss swards. Examples of suitable grasses are Stenotaphrum secundatum (St. Augustine grass), Cynosurus cristatus, Lolium multiflorum and perenne, Agrostis tenuis, Cynodon dactylon (Bermuda grass), Dactylis glomerata, Festuca spp. (e.g. Festuca rubra) and Poa spp. (e.g. Poa pratense). The compounds may stunt grasses without significant phytotoxic effects and without deleteriously affecting the appearance (particularly the colour) of the grass; this makes such compounds attractive for use on ornamental lawns and on grass verges. They may also have an effect on flower head emergence in for example grasses. The compounds can also stunt weed species present in the grasses; examples of such weed species are sedges (e.g. Cyperus spp.) and dicotyledonous weeds (e.g. daisy, plantain, knotweed, speedwell, thistle, docks and ragwort). The growth of non-crop vegetation (eg. weeds or cover vegetation) can be retarded thus assisting in the maintenance of plantation and field crops. In fruit orchards, particularly orchards subject to soil erosion, the presence of grass cover is important. However excessive grass growth requires substantial maintenance. The compounds of the invention could be useful in this situation as they could restrict growth without killing the plants which would lead to soil erosion; at the same time the degree of competition for nutrients and water by the grass would be reduced and this could result in an increased yield of fruit. In some cases, one grass species may be stunted more than another grass species; this selectivity could be useful for example for improving the quality of a sward by preferential suppression of the growth of undesirable species.

The dwarfing may also be useful in miniaturising ornamental, household, garden and nursery plants (eg. poinsettias, chrysanthemums, carnations, tulips and daffodils).

As indicated above, the compounds can also be used to stunt woody species. This property can be used to control hedgerows or to shape or reduce the need for pruning, of fruit trees (eg. apples, pears, cherries, peaches, vines etc). Some coniferous trees are not significantly stunted by the compounds so the compounds could be useful in controlling undesirable vegetation in conifer nurseries.

The plant growth regulating effect may (as implied above) manifest itself in an increase in crop yield; or in an ability in orchards and other crops to increase fruit set, pod set and grain set.

In the potato, haulm control in the field and inhibition of sprouting in the store may be possible.

Other plant growth regulating effects caused by the compounds include alteration of leaf angle and changes in leaf morphology (both of which may permit increased light interception and utilization) and promotion of tillering in monocotyledonous plants. Improved light interception is of value in all major world crops, eg. wheat, barley, rice, maize, soya, sugarbeet, potatoes, plantation crops and orchard crops. The leaf angle effect may be useful for example in altering the leaf orientation of, for example, potato crops thereby letting more light into the crops and inducing an increase in photosynthesis and tuber weight. By increasing tillering in monocotyledonous crops (eg. rice), the number of flowering shoots per unit area may be increased thereby increasing the overall grain yield of such crops. In addition better control and modification of hierarchical relationships is possible both in vegetative and reproductive stages of monocotyledonous and dicotyledenous plant growth, especially in cereals such as wheat, barley, rice and maize, whereby the number of flowering shoots per unit area may be increased and the size distribution of grains within the ear may be modified in such a way as to increase yield. In the treatment of rice plants, or rice crops the invention compounds can be applied, eg. as granules or a granular formulation, for example as slow release granules, to nursery boxes, paddy water and other like cultivation loci and media. In grass swards, especially amenity grass, an increase in tillering could lead to a denser sward which may result in increased resilience in wear; and to increased yields and better quality of forage grass, eg. improved digestability and palatability.

The treatment of plants with the compounds can lead to the leaves developing a darker green colour. In dicotyledonous plants such as soyabean and cotton, there may be promotion of sideshooting.

The compounds may inhibit, or at least delay, the flowering of sugar beet (and thereby may increase sugar yield) or otherwise modify the flowering patterns in many other crops. They may also reduce the size of sugar beet without reducing significantly the sugar yield thereby enabling an increase in planting density to be made. Similarly in other root crops (eg. turnip, swede, mangold, parsnip, beetroot, yam and cassava) it may be possible to increase the planting density.

The compounds could be useful in restricting the vegetative growth of cotton thereby leading to an increase in cotton yield. Crop yields may also be increased by improvement of the harvest index (ie. the harvested yield as a proportion of the total dry matter produced) by altering dry matter partitioning. This applies to all the aforements root, pod cereal, tree, plantation and orchard crops.

The compounds may be useful in rendering plants resistant to stress since the compounds can delay the emergence of plants grown from seed, shorten stem height and delay flowering; these properties could be useful in preventing frost damage in countries where there is significant snow cover in the winter since then the treated plants would remain below snow cover during the cold weather. Further the compounds may cause drought or cold resistance in certain plants.

When applied as seed treatments at low rates the compounds can have a growth stimulating effect on plants.

In carrying out the plant growth regulating method of the invention, the amount of compound to be applied to regulate the growth of plants will depend upon a number of factors, for example the particular compound selected for use, and the identity of the plant species whose growth is to be regulated. However, in general an application rate of 0.1 to 15, preferably 0.1 to 5, kg per hectare is used. With the use of biodegradable polymeric slow release granules rates of 1 to 10 g per hectare are feasible; whilst electrodynamic spraying techniques may also deploy lower rates of application. However, on certain plants even application rates within these ranges may give undesired phytotoxic effects. Routine tests may be necessary to determine the best rate of application of a specific compound for any specific purpose for which it is suitable.

The compounds may be used as such for fungicidal or plant growth regulating purposes but are more conveniently formulated into compositions for such usage. The invention thus provides a fungicidal or plant growth regulating composition comprising a compound of general formula (I) as hereinbefore defined, or a salt, metal complex, ether or ester thereof; and, optionally, a carrier or diluent.

The invention also provides a method of combating fungi, which comprises applying to a plant, to seed of a plant, or to the locus of the plant or seed, a compound, or salt, metal complex, ether or ester thereof, as hereinbefore defined.

The invention also provides a method of regulating plant growth, which comprises applying to the plant, to seed of a plant or to the locus of a plant or seed, a compound, or salt, metal complex, ether or ester thereof, as hereinbefore defined. Compounds Nos. 2, 5 and 6 are especially preferred for this latter purpose.

The compounds, salts, metal complexes, ethers and esters can be applied in a number of ways, for example they can be applied, formulated or unformulated, directly to the foliage of a plant, or they can be applied also to bushes and trees, to seeds or to other medium in which plants, bushes or trees are growing or are to be planted, or they can be sprayed on, dusted on or applied as a cream or paste formulation, or they can be applied as a vapour; or as slow release granules. Application can be to any part of the plant, bush or tree, for example to the foliage, stems, branches or roots, or to soil surrounding the roots, or to the seed before it is planted; or to the soil generally, to paddy water or to hydroponic culture systems. The invention compounds may also be injected into plants or trees and they may also be sprayed onto vegetation using electrodynamic spraying techniques.

The term "plant" as used herein includes seedlings, bushes and trees. Furthermore, the fungicidal method of the invention includes preventative, protectant, prophylactic and eradicant treatment.

The compounds are preferably used for agricultural and horticultural purposes in the form of a composition. The type of composition used in any instance will depend upon the particular purpose envisaged.

The compositions may be in the form of dusting powders or granules comprising the active ingredient and a solid diluent or carrier, for example fillers such as kaolin, bentonite, kieselguhr, dolomite, calcium carbonate, talc, powdered magnesia, Fuller's earth, gypsum, Hewitt's earth, diatomaceous earth and China clay. Such granules can be preformed granules suitable for application to the soil without further treatment. These granules can be made either by impregnating pellets of filler with the active ingredient or by pelleting a mixture of the active ingredient and powdered filler. Compositions for dressing seed, for example, may comprise an agent (for example a mineral oil) for assisting the adhesion of the composition to the seed; alternatively the active ingredient can be formulated for seed dressing purposes using an organic solvent (for example N-methylpyrrolidone or dimethylformamide).

The compositions may also be in the form of dispersible powders, granules or grains comprising a wetting agent to facilitate the dispersion in liquids of the powder or grains which may contain also fillers and suspending agents.

The aqueous dispersions or emulsions may be prepared by dissolving the active ingredient(s) in an organic solvent optionally containing wetting, dispersing or emulsifying agent(s) and then adding the mixture to water which may also contain wetting, dispersing or emulsifying agent(s). Suitable organic solvents are ethylene dichloride, isopropyl alcohol, propylene glycol, diacetone alcohol, toluene, kerosene, methylnaphthalene, the xylenes, trichloroethylene, furfuryl alcohol, tetrahydrofurfuryl alcohol, and glycol ethers (eg. 2-ethoxyethanol and 2-butoxyethanol).

The compositions to be used as sprays may also be in the form of aerosols wherein the formulation is held in a container under pressure in the presence of a propellant, eg. fluorotrichloromethane or dichlorodifluoromethane.

The compounds can be mixed in the dry state with a pyrotechnic mixture to form a composition suitable for generating in enclosed spaces a smoke containing the compounds.

Alternatively, the compounds may be used in a microencapsulated form. They may also be formulated in biodegradable polymeric formulations to obtain a slow, controlled release of the active substance.

By including suitable additives, for example additives for improving the distribution, adhesive power and resistance to rain on treated surfaces, the different compositions can be better adapted for various utilities.

The compounds can be used as mixtures with fertilisers (eg. nitrogen-, potassium- or phosphorus-containing fertilisers). Compositions comprising only granules of fertiliser incorporating, for example coated with, the compound are preferred. Such granules suitably contain up to 25% by weight of the compound. The invention therefore also provides a fertiliser composition comprising the compound of general formula (I) or a salt or metal complex thereof.

The compositions may also be in the form of liquid preparations for use as dips or sprays which are generally aqueous dispersions or emulsions containing the active ingredient in the presence of one or more surfactants eg. wetting agent(s), dispersing agent(s), emulsifying agent(s) or suspending agent(s); or which are spray formulations of the kind suitable for use in electrodynamic spraying techniques. The foregoing agents can be cationic, anionic or non-ionic agents. Suitable cationic agents are quaternary ammonium compounds, for example cetyltrimethylammonium bromide.

Suitable anionic agents are soaps, salts of aliphatic monoesters of sulphuric acid (for example sodium lauryl sulphate), and salts of sulphonated aromatic compounds (for example sodium dodecylbenzenesulphonate, sodium, calcium or ammonium lignosulphonate, butylnaphthalene sulphonate, and a mixture of sodium diisopropyl- and triisopropyl-naphthalene sulphonates).

Suitable non-ionic agents are the condensation products of ethylene oxide with fatty alcohols such as oleyl or cetyl alcohol, or with alkyl phenols such as octyl- or nonyl-phenol and octylcresol. Other non-ionic agents are the partial esters derived from long chain fatty acids and hexitol anhydrides, the condensation products of the said partial esters with ethylene oxide, and the lecithins. Suitable suspending agents are hydrophilic colloids (for example polyvinylpyrrolidone and sodium carboxymethylcellulose), and the vegetable gums (for example gum acacia and gum tragacanth).

The compositions for use as aqueous dispersions or emulsions are generally supplied in the form of a concentrate containing a high proportion of the active ingredient(s), and the concentrate is to be diluted with water before use. These concentrates often should be able to withstand storage for prolonged periods and after such storage be capable of dilution with water in order to form aqueous preparations which remain homogeneous for a sufficient time to enable them to be applied by conventional and electrodynamic spray equipment. The concentrates may conveniently contain up to 95%, suitably 10-85%, for example 25-60%, by weight of the active ingredient(s). These concentrates suitably contain organic acids (eg. alkaryl or aryl sulphonic acids such as xylenesulphonic acid or dodecyl benzenesulphonic acid) since the presence of such acids can increase the solubility of the active ingredient(s) in the polar solvents often used in the concentrates. The concentrates suitably contain also a high proportion of surfactants so that sufficiently stable emulsions in water can be obtained. After dilution to form aqueous preparations, such preparations may contain varying amounts of the active ingredient(s) depending upon the intended purpose, but an aqueous preparation containing 0.0005% or 0.01% to 10% by weight of active ingredient(s) may be used.

The compositions of this invention can comprise also other compound(s) having biological activity, eg. compounds having similar or complementary fungicidal or plant growth activity or compounds having plant growth regulating, herbicidal or insecticidal activity.

The other fungicidal compound can be, for example, one which is capable of combating ear diseases of cereals (eg. wheat) such as Septoria, Gibberella and Helminthosporium spp., seed and soil borne diseases and downy and powdery mildews on grapes and powdery mildew and scab on apple etc. These mixtures of fungicides can have a broader spectrum of activity than the compound of general formula (I) alone; further the other fungicide can have a synergistic effect on the fungicidal activity of the compound of general formula (I). Examples of the other fungicidal compound are imazalil, benomyl, carbendazim, thiophanate-methyl, captafol, captan, sulphur, triforine, dodemorph, tridemorph, pyrazophos, furalaxyl, ethirimol, tecnazene, dimethirimol, bupirimate, chlorthalonil, vinclozolin, procymidone, iprodione, metalaxyl, fosetyl-aluminium, carboxin, oxycarboxin, fenarimol, nuarimol fenfuram, methfuroxam, nitrothal-isopropyl, triadimefon, thiabendazole, etridiazole, triadimenol, biloxazol, dithianon, binapacryl, quinomethionate, guazatine, dodine, fentin acetate, fentin hydroxide, dinocap, folpet, dichlofluanid, ditalimfos, kitazin, cycloheximide, diclobutrazol, a dithiocarbamate, a copper compound, a mercury compound, 1-(2-cyano-2-methoxyiminoacetyl)-3-ethyl urea, fenapanil, ofurace, propiconazole, etaconazole and fenpropemorph.

The compounds of general formula (I) can be mixed with soil, peat or other rooting media for the protection of plants against seed-borne, soil-borne or foliar fungal diseases.

Suitable insecticides are Pirimor, Croneton, dimethoate, Metasystox and formothion.

The other plant growth regulating compound can be one which controls weeds or seedhead formation, improves the level or longevity of the plant growth regulating activity of the compounds of general formula (I), selectively controls the growth of the less desirable plants (eg. grasses) or causes the compound of general formula (I) to act faster or slower as a plant growth regulating agent. Some of these other agents will be herbicides.

Examples of suitable plant growth regulating compounds, which can display synergy in admixture, or use, with the invention compounds are the gibberellins (eg. GA₃, GA₄ and GA₇), the auxins (eg. indoleacetic acid, indolebutyric acid, naphthoxyacetic acid or naphthylacetic acid), the cytokinins (eg. kinetin, diphenylurea, benzimidazole, benzyladenine or benzylaminopurine), phenoxyacetic acids (eg. 2,4-D or MCPA), substituted benzoic acids (eg. triiodobenzoic acid), morphactins (eg. chlorfluorecol), maleic hydrazide, glyphosate, glyphosine, long chain fatty alcohols and acids, dikegulac, paclobutrazol, flurprimidol, fluoridamid, mefluidide, substituted quaternary ammonium and phosphonium compounds (eg. chlormequat* chlorphonium or mepiquatchloride), ethephon, carbetamide, methyl-3,6-dichloroanisate, daminozide*, asulam, abscisic acid, isopyrimol, 1-(4-chlorophenyl)-4,6-dimethyl-2-oxo-1,2-dihydropyridine-3-carboxylic acid, hydroxybenzonitriles (eg. bromoxynil), difenzoquat, benzoylprop-ethyl 3,6-dichloropicolinic acid, and tecnazene. Synergy will be most likely to occur with those of the foregoing which are quaternary ammonium compounds in particular those marked with an asterisk.

The use of the compounds of general formula (I) in conjunction with gibberellins can be useful where it is desired to reduce the plant growth regulating effects of the compounds (eg. where they are to be used as fungicides). Where the compounds are being applied to the soil surrounding the plants or to the roots of the plant, the plant growth regulating effects of the compounds may possibly be reduced by using also certain types of phenoxybenzoic acids and their derivatives.

The following Examples illustrate the invention; the temperatures are given in degrees Centrigrade (°C.).

EXAMPLE 1

This Example illustrates the preparation of diethyl-1-(2,4-dichlorophenyl)-1-hydroxy-2-(1,2,4-triazol-1-yl)-ethylphosphonate. (Compound No 1 of Table I).

A mixture of 2-(1,2,4-triazol-1-yl)-2',4'-dichloroacetophenone (0.005 mol, 1.25 g) and diethyl phosphite (0.01 mol, 1.46 g) was stirred at room temperature with powdered caesium fluoride (0.015 mol, 2.3 g) for 2 hours. The reaction mixture was diluted with ether (50 ml), filtered, the ethereal layer washed with water (3×50 ml), and dried over anhydrous magnesium sulphate. Removal of the solvent gave an oil which was purified by flash chromatography (silica crosfield 210 eluted with ethyl acetate/ethanol (4:1) to give the title compound (1.0 g) as a white crystalline solid m.p. 85°-86° C.

EXAMPLE 2

This Example illustrates the preparation of diisopropyl-1-(4-fluorophenyl)-1-hydroxy-2-(1,2,4-triazol-1-yl)-ethyl phosphonate (Compound No 6 of Table I).

A mixture of 2-(1,2,4-triazol-1-yl)-4'-fluoroacetophenone (0.01 mol, 2.1 g) and diisopropyl phosphite (0.01 mol, 1.66 g) was stirred at room temperature with powdered caesium fluoride (0.02 mol, 3.04 g) for 2 hours. Methylene chloride (150 ml) was added; the methylene chloride extract was filtered, washed with water (3×100 ml), and dried over anhydrous sodium sulphate. Removal of the solvent gave an oil which solidified on standing to give a white solid. Recrystallisation from petroleum ether/methylenechloride gave the title compound (2.1 g) as a white solid m.p. 131°-132° C.

EXAMPLE 3

This Example illustrates the preparation 1-(4-fluorophenyl)-1-hydroxyl-2-(1,2,4-triazol-1-yl)-ethylphosphonic acid. (Compound No 7 of Table I).

A mixture of 2-(1,2,4-triazol-1-yl)-4'-fluoroaceto phenone (0.01 mol, 2.1 g) and diethyl phosphite (0.01 mol, 1.38 g) was stirred at room temperature with powdered caesium fluoride (0.02 mol, 3.04 g) for 2 hours. Methylene chloride (150 ml) was added; the methylene chloride extract filtered, washed with water (3×100 ml), and dried over anhydrous sodium sulphate. Removal of the solvent gave a white solid which recrystallised from petroleum ether/methylene chloride to give diethyl-1-(4-fluorophenyl)-1-hydroxy-2-(1,2,4-triazol-1-yl)-ethylphosphonate (0.9 g) as a white crystalline solid m.p. 118°-119° C. (Compound No 3 of Table I).

A mixture of diethyl-1-(4-fluorophenyl)-1-hydroxy-2-(1,2,4-triazol-1-yl)ethylphosphonate (0.7 g) and trimethyl silyl bromide (3 ml) in methylene chloride (10 ml) was stirred at room temperature for 24 hours. The solvent was removed at the water pump, methanol added to the residue, and this was removed to give a foam. This solidified on trituration with diethyl ether to give the title compound as a white solid m.p. 185°-186° C. (HBr salt).

EXAMPLE 4

An emulsifiable concentrate was made up by mixing the ingredients, and stirring the mixture until all the constituents were dissolved.

Compound of Example 1: 10%

Ethylene dichloride: 40%

Calcium dodecylbenzenesulphate: 5%

"Lubrol" L: 10%

"Aromasol" H: 35%

EXAMPLE 5

A composition in the form of grains readily dispersible in a liquid, e.g. water, was prepared by grinding together the first three ingredients in the presence of added water and then mixing in the sodium acetate. The resultant mixture was dried and passed through a British Standard mesh sieve, size 44-100, to obtain the desired size of grains.

Compound of Example 2: 50%

"Dispersol" T: 25%

"Lubrol" APN5: 1.5%

Sodium acetate: 23.5%

EXAMPLE 6

The ingredients were all ground together to produce a powder formulation readily dispersible in liquids.

Compound of Example 3: 45%

"Dispersol" T: 5%

"Lissapol" NX: 0.5%

"Cellofas" B600: 2%

Sodium acetate: 47.5%

EXAMPLE 7

The active ingredient was dissolved in a solvent and the resultant liquid was sprayed on to the granules of China clay. The solvent was then allowed to evaporate to produce a granular composition.

Compound of Example 3: 5%

China clay granules: 95%

EXAMPLE 8

A composition suitable for use as a seed dressing was prepared by mixing the three ingredients.

Compound of Example 1: 50%

Mineral oil: 2%

China clay: 48%

EXAMPLE 9

A dusting powder was prepared by mixing the active ingredient with talc.

Compound of Example 2: 5%

Talc: 95%

EXAMPLE 10

A Col formulation was prepared by ball-milling the constituents set out below and then forming an aqueous suspension of the ground mixture with water.

Compound of Example 3: 40%

"Dispersol" T: 10%

"Lubrol" APN5: 1%

Water:

EXAMPLE 11

A dispersible powder formulation was made by mixing together the ingredients set out below and then grinding the mixture until all were thoroughly mixed.

Compound of Example 1: 25%

"Aerosol" OT/B: 2%

"Dispersol" A.C.: 5%

China clay: 28%

Silica: 40%

EXAMPLE 12

This Example illustrates the preparation of a dispersible powder formulation. The ingredients were mixed and the mixture then ground in a comminution mill.

Compound of Example 1: 25%

"Perminal" BX: 1%

"Dispersol" T: 5%

Polyvinylpyrrolidone: 10%

Silica: 25%

China clay: 34%

EXAMPLE 13

The ingredients set out below were formulated into a dispersible powder by mixing then grinding the ingredients.

Compound of Example 2: 25%

"Aerosol" OT/B: 2%

"Dispersol" A: 5%

China clay: 68%

In Examples 4 to 13 the proportions of the ingredients given are by weight.

All the compounds set out in Table I were similarly formulated as specifically described in Examples 4 to 13.

There now follows an explanation of the compositions or substances represented by the various Trade Marks and Trade Names mentioned above.

LUBROL L: a condensate of nonyl phenol 1 mole) with ethylene oxide (13 moles)

AROMASOL H: a solvent mixture of alkylbenzenes

DISPERSOL T & AC: a mixture of sodium sulphate and a condensate of formaldehyde with sodium naphthalene sulphonate

LUBROL APN5: a condensate of nonyl phenyl (1 mole) with naphthalene oxide (5.5 moles)

CELLOFAS B600: a sodium carboxymethyl cellulose thickener

LISSAPOL NX: a condensate of nonyl phenol (1 mole) with ethylene oxide (8 moles)

AEROSOL OT/B: dioctyl sodium sulphosuccinate

PERMINAL BX: a sodium alkyl naphthalene sulphonate

EXAMPLE 14

The compounds were tested against a variety of foliar fungal diseases of plants. The technique employed was as follows.

The plants were grown in John Innes Potting Compost (No 1 or 2) in 4 cm diameter minipots. A layer of fine sand was placed at the bottom of the pots containing the dicotyledonous plants to facilitate uptake of test compound by the roots. The test compounds were formulated either by bead milling with aqueous Dispersol T or as a solution in acetone or acetone/ethanol which was diluted to the required concentration immediately before use. For the foliage diseases, the formulations (100 ppm active ingredient) were sprayed on to the foliage and applied to the roots of the plants in the soil. The sprays were applied to maximum retention and the root drenches to a final concentration equivalent to approximately 40 ppm a.i./dry soil. Tween 20, to give a final concentration of 0.05%, was added when the sprays were applied to cereals.

For most of the tests the compound was applied to the soil (roots) and to the foliage (by spraying) one or two days before the plant was inoculated with the disease. An exception was the test on Erysiphe graminis in which the plants were inoculated 24 hours before treatment. Foliar pathogens were applied by spray as spore suspensions onto the leaves of test plants. After inoculation, the plants were put into an appropriate environment to allow infection to proceed and then incubated until the disease was ready for assessment. The period between inoculation and assessment varied from four to fourteen days according to the disease and environment.

The disease control was recorded by the following grading:

4=no disease

3=trace-5% of disease on untreated plants

2=6-25% of disease on untreated plants

1=26-59% of disease on untreated plants

0=60-100% of disease on untreated plants

The results are shown in Table II.

                                      TABLE II                                     __________________________________________________________________________              PUCCINIA ERYSIPHE                                                                               PIRICULARIA                                                                             PLASMOPARA                                                                              CERCOSPORA                                                                               VENTURIA                 COMPOUND RECONDITA                                                                               GRAMINIS                                                                               ORYZAE   VITOCOLA ARACHIDICOLA                                                                             INAEQUALIS               NUMBER   (WHEAT)  (BARLEY)                                                                               (RICE)   (VINE)   (PEANUT)  (APPLE)                  __________________________________________________________________________     1        0        2       1        0        --        0                        2        4        4       0        3        --        4                        3        3        4       2        3        --        4                        4        0        3       0        0        0         0                        5        3        4       0        0        3         4                        6        3        4       0        0        3         4                        7        0        0       0        0        0         0                        8        3        3       3        0        0         1                        13       0        4       0        0        0         0                        __________________________________________________________________________      "--" means not tested.                                                   

EXAMPLE 15

This Example illustrates the plant growth regulating properties of the compounds. The compounds were applied as an overall spray of an emulsifiable concentrate diluted to give the concentrations shown in Table III. The plants were grown in 3" pots in peat compost and sprayed at the 2 leaf stage. Plant growth regulating effects were assessed 13 or 19 days after application of the compounds. Retardation of growth was scored on a 1-3 scale where:

1=0-30% retardation

2=31-75% retardation

3=75% retardation or more

The absence of any numeral 1 to 3 signifies no effect.

Additional plant growth regulating properties are indicated as follows:

G=darker green leaf colour

H=paler green leaf colour

A=apical effect

T=tillering effect/sideslooking

The results are shown in Table III. If no figure is shown the compounds was substantially inactive as a stunting agent.

                                      TABLE III                                    __________________________________________________________________________                     AT  CC DA LT SB TO SY CT MZ WW BR VN RA                        COMPOUND                                                                               DAT RATE                                                                               (ppm)                                                          __________________________________________________________________________     1       19  4000                                                                               --  -- -- 1  1G 1GA                                                                               3A -- -- T  T  1A --                        2       18  4000                                                                               2G  2G 1  -- 2GA                                                                               3GA                                                                               1G 2A -- 3G 3GT                                                                               2A 3AG                       3       19  4000                                                                               1   1  -- 1A 1G -- 1  -- 1  3TG                                                                               2T 3G --                        4       18  3000                                                                               --  -- -- 2  1G 1GT                                                                               1GT                                                                               1G -- -- -- 1  3AG                       5       18  4000                                                                               3   2  2  3A 2G 3A 2GA                                                                               3A -- 3G 3G 3A 3AG                       6       18  4000                                                                               2   2  1  2A 2GA                                                                               3GA                                                                               1G 3A -- 2G 2GT                                                                               3A 2AG                       7       19  4000                                                                               --  -- -- -- 1  1  1  -- -- 1  1T -- --                        8       19  4000                                                                               1   -- -- -- 1G 1  -- -- 1G T  T  2  --                        13      19  4000                                                                               --  -- -- -- -- -- G  -- -- -- -- 3  --                        __________________________________________________________________________      Key to test species in Table III                                               AT Agrostis tenuis                                                             CC Cynosurus cristatus                                                         DA Dactylis glomerata                                                          LT Lactuca sativa                                                              SB Beta vulgaris                                                               TO Lycopersicum esculentum                                                     SY Glycine max                                                                 CT Gossypium hirsutum                                                          MZ Zea mays                                                                    WW Triticum aestivum                                                           BR Hordeum vulgare                                                             VN Vitis vinifera                                                              RA Rapharus raphinistrum                                                  

We claim:
 1. A compound of the formula (I): ##STR9## and stereoisomers thereof, wherein R¹ and R² are each hydrogen, an alkali metal, quaternary ammonium or sulphonium cation, C₁₋₆ alkyl, C₃₋₆ cycloalkyl, phenyl or benzyl, phenyl or benzyl substituted with halogen, nitro, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, phenyl, phenoxy, halophenyl or halophenoxy; R³ and R⁴ are each hydrogen, C₁₋₆ alkyl, phenyl or benzyl or phenyl or benzyl substituted with halogen, nitro, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, phenyl, phenoxy, halophenyl or halophenoxy; W is N or CH; X is oxygen or sulphur; acetic, propionic or benzoic acid esters or methyl, ethyl, propyl, butyl or benzyl ethers of the alcohol; acid addition salts of said compound or metal complexes thereof, with the proviso that one of R³ and R⁴ is other than hydrogen or alkyl of 1-6 carbons.
 2. A compound according to claim 1 wherein R¹ and R² are hydrogen or C₁₋₆ alkyl; R³ and R⁴ are hydrogen, phenyl or benzyl or phenyl or benzyl substituted with halogen, nitro, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, phenyl, phenoxy, halophenyl or halophenoxy, provided that at least one of R³ and R⁴ is other than hydrogen; and X is oxygen.
 3. A compound according to claim 2 wherein R¹ and R² are hydrogen or C₁₋₄ alkyl and R³ and R⁴ are hydrogen, phenyl or benzyl or phenyl or benzyl substituted with halogen or C₁₋₆ alkoxy provided that at least one of R³ and R⁴ is other than hydrogen.
 4. A compound according to claim 3 wherein R¹ and R² are hydrogen, methyl, ethyl, propyl or butyl.
 5. A compound as defined in claim 4 wherein R³ and R⁴, which may be the same or different, are hydrogen, phenyl, benzyl, 2-, 3- or 4-chlorophenyl, 2,4- or 2,6-dichlorophenyl, 2-, 3- or 4-fluorophenyl, 2,4- or 2,6-difluorophenyl, 2-, 3- or 4-bromophenyl, 2-chloro-4-fluorophenyl, 2-chloro-6-fluorophenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-ethoxyphenyl, 2-, 3- or 4-nitrophenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-t-butylphenyl, 2-, 3- or 4-trifluoromethylphenyl, 2-, 3- or 4-phenoxyphenyl, 2-, 3- or 4-phenylphenyl, 2-chloro-4-methylphenyl, and 2-chloro-4-methoxyphenyl, or (the correspondingly) substituted benzyl groups wherein the phenyl group is 2-, or 3- or 4-chlorophenyl 2,4- or 2,6-dichlorophenyl, 2-, 3- or 4-fluorophenyl, 2,4- or 2,6-difluorophenyl, 2-, 3- or 4-bromophenyl, 2-chloro-4-fluorophenyl, 2-chloro-6-fluorophenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-ethoxyphenyl, 2-, 3- or 4-nitrophenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-t-butylphenyl, 2-, 3- or 4-trifluoromethylphenyl, 2-, 3- or 4-phenoxyphenyl, 2-, 3- or 4-phenylphenyl, 2-chloro-4-methylphenyl, and 2-chloro-4-methoxyphenyl, provided that at least one of R³ and R⁴ is other than hydrogen.
 6. A compound according to claim 1 selected from the group consisting of diethyl-1-(4-chlorophenyl)-1-hydroxy-2-(1,2,4-triazol-1-yl)-ethylphosphonate; di-n-butyl-1-(4-fluorophenyl)-1-hydroxy-2-(1,2,4-triazol-1-yl)-ethylphosphonate; and di-iso-propyl-1-(4-fluorophenyl)-1-hydroxy-2-(1,2,4-triazol-1-yl)-ethylphosphonate.
 7. A plant growth regulating composition comprising an effective amount of a compound according to claim 1 and a carrier or diluent therefor.
 8. A method of regulating the growth of plants, which comprises applying to the plant, to seed of the plant, or to the locus of the plant or seed, an effective amount of a compound according to claim
 1. 